Atypical and dual biotypes variant of virulent SA-NAG-Vibrio cholerae: an evidence of emerging/evolving patho-significant strain in municipal domestic water sources
Bright E. Igere, Anthony I. Okoh, Uchechukwu U. Nwodo
Abstract
Abstract Introduction and purpose The recent cholera spread, new cases, and fatality continue to arouse concern in public health systems; however, interventions on control is at its peak yet statistics show continuous report. This study characterized atypical and patho-significant environmental Vibrio cholerae retrieved from ground/surface/domestic water in rural-urban-sub-urban locations of Amathole District municipality and Chris Hani District municipality, Eastern Cape Province, South Africa. Methods Domestic/surface water was sampled and 759 presumptive V. cholerae isolates were retrieved using standard microbiological methods. Virulence phenotypic test: toxin co-regulated pili (tcp), choleragen red, protease production, lecithinase production, and lipase test were conducted. Serotyping using polyvalent antisera (Bengal and Ogawa/Inaba/Hikojima) and molecular typing: 16SrRNA, OmpW, serogroup (Vc-O1/O139), biotype ( tcpAClas/El Tor , HlyAClas/El Tor , rstRClas/El Tor , RS1 , rtxA , rtxC ), and virulence ( ctxA , ctxB , zot , ace , cep , prt , toxR , hlyA ) genes were targeted. Result Result of 16SrRNA typing confirmed 508 (66.9%) while OmpW detected/confirmed 61 (12.01%) V. cholerae strains. Phenotypic-biotyping scheme showed positive test to polymyxin B (68.9%), Voges proskauer (6.6%), and Bengal serology (11.5%). Whereas Vc-O1/O139 was negative, yet two of the isolates harbored the cholera toxin with a gene-type ctxB and hlyAClas : 2/61, revealing atypical/unusual/dual biotype phenotypic/genotypic features. Other potential atypical genotypes detected include rstR : 7/61, Cep : 15/61, ace : 20/61, hlyAElTor : 53/61, rtxA : 30/61, rtxC : 11/61, and prtV : 15/61 respectively. Conclusion Although additional patho-significant/virulent genotypes associated with epidemic/sporadic cholera cases were detected, an advanced, bioinformatics, and post-molecular evaluation is necessary. Such stride possesses potential to adequately minimize future cholera cases associated with dynamic/atypical environmental V. cholerae strains.